This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. A large proportion of dementia cases in the aged population are not due to Alzheimers disease (AD), but rather to cerebrovascular disease. Dementia due to cerebrovascular disease, broadly described as stroke, is referred to as vascular dementia or vascular cognitive impairment (VCI). Despite the enormous prevalence of VCI, the biological basis of this disease has been much less well studied than AD. A striking feature of VCI is that it is difficult to predict based on medical diagnosis alone. This suggests that unknown genetic factors may play a role in a person's susceptibily to develop VCI. This study is designed to accurately measure cerebrovascular disease through magnetic resonance imaging (MRI) and cognitive ability(through a battery of tests for intellectual functioning) in a population of families highly enriched for the presence of type 2 diabetes, the Diabetes Heart Study (DHS). The DHS has recruited over 1200 subjects from 450 families and has extensive sophisticated measures of atherosclerosis, body composition, bone density, and other clinical measures. In addition, as part of the DHS, a genome-wide scan is being performed which will create a database of inheritance markers for each part of each chromosome in each individual. Family members will be given MRI scans and cognitive tests. Initially we will estimate the extent that genetics contributes to cerebrovascular disease and cognitive impairment (i.e. estimates of heritability) in the DHS families. Second, results from the MRI scans and cognitive tests will be used to map genes that influence these traits.